In a Long Term Evolution (LTE) system, which is a radio communication system, a location management center (Enhanced Serving Mobile Location Centre: hereinafter it will be referred to as an E-SMLC), an LTE base control station (Mobility Management Entity: hereinafter it will be referred to as an MME), and an LTE base station (enhanced Node B: hereinafter it will be referred to as an eNB) transmit and receive a location information control message in order to manage location information of a communication terminal (User Equipment: hereinafter it will be referred to as a UE). The eNB includes a small radio base station (Home enhanced Node B: hereinafter it will be referred to as an HeNB).
In the location information control message, there is a location information collection message of the UE and a location-related information collection message of an eNB required to specify the location information of the UE. This specification is mainly related to the location-related information collection message of the eNB.
FIG. 12 shows a network configuration (network architecture) in a location control method of an LTE system according to related art.
As shown in FIG. 12, the LTE system according to the related art includes a UE (N905), a radio base station eNB (N903), a cell (N904) formed of the eNB (N903), an MME (N902) that executes in-network mobility management of the UE (N905), and an E-SMLC (N901) that manages and calculates the location information of the UE (N905) and the eNB (N903). The UE (N905) is located within the cell (N904) and is connected to the eNB (N903). The roles of the respective nodes are disclosed in Non-Patent Literature 1 and 5.
FIG. 13 shows a message sequence according to transmission and reception of a location-related information collection message of the eNB in the location control method of the LTE system according to related art.
In S001, the E-SMLC (N901) transmits an LCS-AP: Connectionless Information message to obtain the location information of the eNB (N903). The details of this message are disclosed in Non-Patent Literature 2. According to the disclosure in Non-Patent Literature 2, a Source Identity, a Destination Identity, and an APDU are set in this message. The Source Identity is an E-SMLC Identity that specifies the E-SMLC, the Destination Identity is a Global eNB Identity that specifies the eNB, and the APDU includes information indicating which kind of information of the eNB is required.
The details of information included in the APDU in the LCS-AP: Connectionless Information message are disclosed in Non-Patent Literature 4. According to Non-Patent Literature 4, one example of the information included in the APDU in the LCS-AP: Connectionless Information message is an LPPa: OTDOA Information Request, which is one information acquisition request of the eNB among location-related information collection messages.
The LPPa: OTDOA Information Request message includes an LPPa Transaction ID and an OTDOA Information Item. The LPPa Transaction ID indicates an ID that specifies one information collection and acquisition process and the OTDOA Information Item includes an information item of the eNB that the E-SMLC requires (e.g. pci, cellid, tac, earfcn, prsBandwidth, prsConfiglndex, cpLength, noDlFrames, noAntennaPorts, sFNlnitTime, . . . , e-UTRANAccessPointPosition, prsmutingconfiguration). Since each item is typical information as the location-related information of the LTE system and the eNB, the details thereof will be omitted.
In S002, the MME (N902) determines the eNB to which the location-related control message will be transmitted according to the configuration of the Global eNB ID of the Destination Identity included in the LCS-AP: Connectionless Information message received from the E-SMLC in S001.
In S003, the MME (N902) transmits an S1AP: DOWNLINK NON UE ASSOCIATED LPPA TRANSPORT message to the eNB determined in S002. The details of this message are disclosed in Non-Patent Literature 3. According to Non-Patent Literature 3, this message includes a Routing ID and an LPPa-PDU, the Routing ID has a desired value from 0 to 255, and the E-SMLC Identity may be set in this message. The LPPa-PDU includes the APDU included in the LCS-AP: Connectionless Information message received from the E-SMLC in S001. Specific examples of the LPPa-PDU include an LPPa: OTDOA Information Request.
In S004, the eNB (N903) collects the location-related information of the eNB (N903) according to the OTDOA Information Item included in the OTDOA Information Request received in S003.
In S005, the eNB (N903) transmits an S1AP: UPLINK NON UE ASSOCIATED LPPA TRANSPORT message to the MME (N902). The details of this message are disclosed in Non-Patent Literature 3. According to Non-Patent Literature 3, this message includes a Routing ID and an LPPa-PDU. The Routing ID sets a value the same as the S1AP: DOWNLINK NON UE ASSOCIATED LPPA TRANSPORT message received in S003 and the LPPa-PDU includes eNB location-related information.
The details of the information included in the LPPa-PDU in the S1AP: UPLINK NON UE ASSOCIATED LPPA TRANSPORT message are disclosed in Non-Patent Literature 4. According to Non-Patent Literature 4, the information included in the LPPa-PDU in the S1AP: UPLINK NON UE ASSOCIATED LPPA TRANSPORT message corresponds to an LPPa: OTDOA Information Response, which is one response message of the eNB. The LPPa: OTDOA Information Response message includes the LPPa Transaction ID and the OTDOA Cell Information for the number of cells that the eNB forms. The LPPa Transaction ID is the same as the value set in the LPPa: OTDOA Information Request message included in the S1AP: DOWNLINK NON UE ASSOCIATED LPPA TRANSPORT message received in S003. The OTDOA Cell Information is set in the LPPa: OTDOA Information Request message included in the S1AP: DOWNLINK NON UE ASSOCIATED LPPA TRANSPORT message received in S003. The eNB location-related information related to the OTDOA Information Item is set as the OTDOA Cell Information. According to Non-Patent Literature 4, the OTDOA Cell Information is able to set 256 cells at maximum.
In S006, the MME (N902) transmits an LCS-AP: Connectionless Information message corresponding to the LPPa-PDU and the Routing ID included in the S1AP: UPLINK NON UE ASSOCIATED LPPA TRANSPORT message received in S005 to the E-SMLC (N901). As described above, the Source Identity, the Destination Identity, and the APDU are set in this message. The Source Identity sets the Global eNB Identity that specifies the eNB, the Destination Identity sets the E-SMLC Identity that specifies the E-SMLC, and the APDU sets the LPPa-PDU included in the S1AP: UPLINK NON UE ASSOCIATED LPPA TRANSPORT message received in S005. The MME (N902) may manage S003 and S005 in association with S001, construct the message in S006, and transmit the message to the E-SMLC (N901), or may set the information of the eNB that has transmitted the message in S005 and the Routing ID included in S005 as the Source Identity and the Destination Identity of the LCS-AP: Connectionless Information message in S006.
After that, the E-SMLC (N901) stores the information of the eNB (N903) that has been acquired as information necessary for specifying the location information of the UE (N905). By performing a calculation using the information acquired from the UE and the location-related information of the eNB acquired from the eNB, the E-SMLC is able to calculate highly accurate UE location information. The details thereof will be omitted since they do not have a direct relationship with the present specification.
While S001 to S006 indicate transmission and reception of the location information collection message defined in Non-Patent Literature 1, this procedure can be achieved only by the configuration shown in FIG. 12.